interesting. here's some internet forum speculation I've read on the audi forums. these engines only had 4.0 qt capacities, only used dino oil, and had no electric oil pump or cooling for the turbos after the engine gets shut off. All in stark contrast to the bmw setup (7 qts, oil cools turbo after shutdown (I think?), and speciific syn oil).

That's kinda what I thought, synthetic vs dino, I think the water pump cools the turbo though. These intervals will be the norm for most vehicles soon.